title: Methodological considerations in quantification of 3'-deoxy-3'-[18F]fluorothymidine uptake measured with positron emission tomography in patients with non-small cell lung cancer.
abstract: OBJECTIVE
  To investigate the effect of image-derived input functions (IDIF), input function corrections and volume of interest (VOI) size in quantification of [(18)F]FLT uptake in non-small cell lung cancer (NSCLC) patients.
  
  
  METHODS
  Twenty-three NSCLC patients were scanned on a HR+ scanner. IDIFs were defined over the aorta and left ventricle. Activity concentration and metabolite fraction were measured in venous blood samples. Venous blood samples at 30, 40 and 60 min after injection were used to calibrate the IDIF time-activity curves. Adaptive thresholds were used for VOI definition. Full kinetic analysis and simplified measures were performed.
  
  
  RESULTS
  Non-linear regression analysis showed better fits for the irreversible model compared to the reversible model in the majority. Calibrated and metabolite corrected plus plasma-to-blood ratio corrected input function resulted in high correlations between SUV and Patlak K i (Pearson correlation coefficients 0.86-0.96, p value < 0.001). No significant differences in correlation between SUV and Patlak K i were observed with variation of IDIF structure or VOI size.
  
  
  CONCLUSIONS
  Plasma-to-blood ratio correction, metabolite correction and calibration improved the correlation between SUV and Patlak K i significantly, indicating the need for these corrections when K i is used to validate semi-quantitative measures, such as SUV.
authors.affiliation: Department of Radiology & Nuclear Medicine, VU University Medical Center (VUmc), P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.
authors.forename: Virginie
authors.initials: V
authors.lastname: Frings
authors.forename: Adrianus J
authors.initials: AJ
authors.lastname: de Langen
authors.forename: Maqsood
authors.initials: M
authors.lastname: Yaqub
authors.forename: Robert C
authors.initials: RC
authors.lastname: Schuit
authors.forename: Astrid A M
authors.initials: AA
authors.lastname: van der Veldt
authors.forename: Otto S
authors.initials: OS
authors.lastname: Hoekstra
authors.forename: Egbert F
authors.initials: EF
authors.lastname: Smit
authors.forename: Ronald
authors.initials: R
authors.lastname: Boellaard
mesh_terms: D000328:Adult; D000368:Aged; D002138:Calibration; D002289:Carcinoma, Non-Small-Cell Lung / Q000097:blood / Q000000981:diagnostic imaging*; D003710:Demography; D015224:Dideoxynucleosides / Q000097:blood / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D017711:Nonlinear Dynamics; D049268:Positron-Emission Tomography / Q000379:methods*; D012044:Regression Analysis
chemical_list: D015224:Dideoxynucleosides; C002854:alovudine